Field of the Disclosure
The present disclosure relates to an ophthalmologic photographing apparatus that images an eye to be examined.
Description of the Related Art
In recent years, eye examination is drawing attention since it is effective for early diagnosis of lifestyle diseases and various diseases with high rankings among causes of blindness. Most of all, ophthalmic tomogram acquisition apparatuses such as fundus cameras and optical coherence tomography (OCT: Optical Coherence Tomography), which are used at eye clinics and the like, can quantify the state of a disease. Hence, these apparatuses are expected to be useful to more accurately diagnose diseases. With a general OCT, a photographer determines imaging parameters (for example, a target region, an imaging range, the level of detail, and a scanning method) of a cross-sectional image, and then captures a cross-sectional image of a local region of an eye on the basis of the imaging parameters. Moreover, an ophthalmologic photographing apparatus is known which accepts, from a user, a specification of an imaging position for a cross-sectional image on a screen where a front fundus image of a fundus camera or a scanning laser ophthalmoscope (SLO: Scanning Laser Ophthalmoscope) is displayed, and captures the cross-sectional image.
If changes in the condition of the same region of the same patient are observed such as an observation of the progress of a disease of an eye, the prescription of drugs, and post-operative follow-up, it is required to capture cross-sectional images of the same region at intervals over a long time. Furthermore, comparisons of fewer wide-area and high-definition cross-sectional images of the same region that captured a lesion are suitable for comparisons of secular changes.
Moreover, an eye moves to change the line of sight, for example, involuntary eye movement, even during fixation, it is difficult to fix the position of an eye of an examinee. Hence, it is difficult to cause the eye to stay at the same coordinates in a coordinate system of the apparatus and capture an image of the eye. Japanese Patent Laid-Open No. 2008-289642 discloses an OCT apparatus including a tracking function that determines the suitability of a fixation state of an eye to be examine while a fixation target is being presented and, if the fixation state is judged to be inappropriate, corrects the position of an imaging area being a position for acquiring a tomographic image on the basis of the displacement of the eye to be examined.